Comcast Corp. has agreed to buy Radiance Technologies Inc., a Los Altos, Calif.-based provider of digital delivery solutions for the advertising and enterprise sectors. The deal is valued at around $5 million. Radiance had raised over $26 million in VC funding since 2000, including a round last year at a $34 million post-money valuation. Backers included Sutter Hill Ventures, Levensohn Venture Partners and Chevron Technology Ventures. www.radiance.com